Derbi Senda Electrics

[Keith.o2]

Hi,
Can any body help me with my sons derbi senda electrics, the rear indicators flash rapidly and are dim the front do not flash at all, the horn is not very loud and the rear break light is not coming on, i have replace the relay/retifier unit and repaced the battery but still no luck, has anybody got any ideas of what to do next.

Thanks
Keith

[BigBen]

to be honest starting again is probably the easiest, what year bike is it? i had a 1996 senda and the wires were rotted through and people like to try and “play” with wires and they just end up in a state.

maybe stating the obvious but the front indicator bulbs arnt blown are they? when bulbs blow the other bulbs tend to flash faster as theres not as much load on the relay (if that was expressed correctly).
OR there may be a bad earth somewhere.

the horn could quite possibly be knackered if its an old one.

and i had problems with the rear brake light too..the terminals tend to get covered in crap as all the mud can colect in the undertray, so have a clean out, remove the rear brake light and scratch off the crap and use contact cleaner on it…also the terminals on mine needed bending in to make contact with the terminals on the bulb so check if theres clearance between the two and correct if there is..

hope this is of some use.

[katana]

Like ben says its likely to be dodgy wiring.

Sounds to me like a classic bad earth problem. Follow the earth from the battery and make sure that it is not corroded where it connects to the frame, there might also be an earth wire from the frame to the engine – check that too. Try running an earth directly from the battery to the front indicators and see if it cures that problem. failing that its cleaning all connectors and looking for obviously damaged wires.

Let us know how you get on

[katana]

Not sure if you have a wiring diagram – if not here’s a copy of the manual:

scootercool.nl/manual6speed.pdf

[Keith.o2]

Got the diagram, i will try all the ideas out the weekend, thanks for all the info, one other thing, the rear indicators have been replaced, if the wires where crossed over would this give any problems ?

Thanks
Keith

[katana]

Are the new indicators LED? If they are that explains the rapid flashing as most LED replacements need balance resistors fitting in parralel or a different (solid state) relay.

[Radar]

Welcome to the forum, I hope the lads tips helped. Let us know how it turns out.

In the meantime this link will help you to explore the site

https://www.bikemeet.net/forums/topic/great-posts-pics-across-the-site-part-2/

[TT07]

Hello Keith, welcome to The Bike Forum, out of interest do you have a biking background? If so what do you have got / what have you owned?

[BigBen]

the wires being crossed over would make no difference as they have only two wires coming out of them, a positive and a negative, if they were connected the wrong way round they would not light up at all.

[imperialdata]

Good advice from the guys above. Just one point:

quote:

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Originally posted by benji_zx10r

the wires being crossed over would make no difference as they have only two wires coming out of them, a positive and a negative, if they were connected the wrong way round they would not light up at all.

---

If they are plastic bodied indicators with no internal earth and a standard lamp (bulb) inside then they should light up both ways.

If they have an internal earth connection and that earth then touches the frame of the bike then this would mean a short circuit when indicating, blowing a fuse or ‘dragging’ the voltage down.

You really need a multimeter to go forward here, do you have one? They are only a few quid and well worth it for times like this. Put it onto DC Volts, clamp the black probe to the battery – terminal and you will then see how many volts you get when you touch the red lead on different parts of the circuit. You can establish which wire is the ‘live’ feed for the indicators on each side.

If the indicators have metal that touches the frame, then disconnect their wires and see if there is continuity between one of the wires and this metal part. If so, then this is your negative wire.

Take care not to touch any live wires when the multimeter is set on continuity.

[BigBen]

my windy caters have never worked both ways

[Keith.o2]

Think I am getting there, just want some confirmation, i bought a new battery and it is reading 12.5 volts, when i connect it, it drops to 4.5 volts, so dissconect both terminals and connect a multimeter to the negative wire, and find the earth on the inicators but i touch the other side of the indicators i get the same reading, so i am assuming that i do have an earth problem, if so ,just got to try and find it

Thanks for all the info.

[imperialdata]

You will get the same continuity reading to the negative side because there is a filament on the bulb passing this continuity through. You will effectively be reading the resistance of the bulb.

You need to disconnect and remove the battery and see what resistance reading you have between the live battery connection wire and earth (you can use the negative connection here as earth). Then disconnect things (like the indicators) and see whether the continuity remains the same or goes higher (higher means less continuity). When it is very high you should be closer to finding the fault which is ‘dragging’ that voltage down.

In short, trace the live path from the battery and see where it has low resistance to earth.

[Author]

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